Licenses

The grid

License	Intended scope	Copyleft	Modifiability	Attribution	Worldwide applicability
Against DRM	-	?	?	?	?
CC BY	-	no	no	yes	national adaptations
CC BY-SA	-	yes	no	yes	national adaptations
Design Science	-	yes	yes	no	same license (English version)
Free Art License	-	yes	no	yes	exact translations
GNU FDL	text documents	yes	yes	no	same license (English version)
GNU GPL	software	yes	yes	no	same license (English version)

Criteria

Intended scope

Some licenses strive to be as generic as is humanly (or rather, legally) possible. Others deliberately focus on a specific domain of creation, like software, or documentation. When a license has such a focus, it doesn't mean that it cannot be used for other kinds of works, but that its main area of use (and thus its social recognition as a trustable license) is clearly bounded.

For example, the GNU GPL can be used for many kinds of works, but its main area of recognition is software.

Copyleft

When a work is "copylefted", it means all derived works (even if they mix in other works as well) must be distributed under the same terms (usually the same exact license) as the original work. Conversely, a non-copylefted work can be distributed under different terms, and even be rendered non-free.

Therefore, using a copyleft license pretty much guarantees that users of subsequent works (for example modified copies) will be granted the same essential freedoms. On the other hand, a copyleft license can also limit opportunities for re-use, because most copyleft licenses are not compatible between each other. This is why people sometimes prefer non-copyleft license, depending on the work and the kind of practices they want to encourage.

Note: ShareAlike is a synonym of copyleft in the Creative Commons vocabulary.

Modifiability

Although all free licenses give you the legal right to modify, not all of them try to specify how modifiability of the work is practically enforced. Requiring modifiability is important, especially for works which can be distributed under a completely opaque format such as software binary code ("object code").

The licenses which require practical modifiability usually define a notion of source code, source data or similar.

License list

Against DRM

• current version: 2.0

Creative Commons licenses

Creative Commons BY

• complete name: Creative Commons Attribution
• current version: 2.5

Creative Commons BY-SA

• complete name: Creative Commons Attribution-ShareAlike
• current version: 2.5

Design Science License

• not maintained anymore

Free Art License

• current version: 1.2

GNU FDL

• complete name: GNU Free Documentation License
• current version: 1.2

GNU GPL

• complete name: GNU General Public License
• current version: 2.0

(to be removed when the page overhaul is finished)

Current draft

Tentatively, the following licenses are known to meet the criteria set out by the definition:

• Creative Commons Attribution License (not free for Debian)
• Creative Commons Attribution/Share-Alike License (not free for Debian)
• GNU Free Documentation License when no invariant sections are specified (this is important)
• Free Art License (not free for Debian)
• Against DRM 2.0
• All free software licenses. While many of them are specific to software, some are worded so as to apply to all kinds of digital works. For example, the GNU GPL is often applied to non-software works (such as computer graphics, game scenarios...).

In addition, works in the public domain are also free content as per the definition.

To be verified:

• Freie Wiki-Lizenz

Controversial:

• IANG license - seeks to enforce lots of things that are outside of the copyright realm (like organization scheme, right of developers to have a voice in the development process, etc.)